This invention relates generally to rear projection television receivers and particularly to the relatively large mirrors used in such projection receivers.
Rear projection type television receivers are very popular due to the large display screens that are available for the enjoyment of the user without necessitating special installations and/or large viewing areas. In such receivers, three color cathode ray tubes (red, green and blue) project an image onto a mirror, with the image being reflected (and magnified) onto a display screen that may comprise a fresnel lens arrangement. The large mirrors, on the order of 40.times.30 inches, are not only expensive, but heavy.
Recently, some rear projection television receiver mirrors have been fabricated of metallized plastic film that is tightly stretched and secured to a relatively light-weight aluminum frame. The technique utilizes a trapezoidal shape, U-shaped frame that is secured to the cabinet (at an appropriate angle) by brackets at its corners, or by welding. A rigid backing, in the form of about a one-half inch thick sheet of styrofoam is secured in the frame very close to the metallized plastic film. The metallized plastic film is stretched, wrapped around the frame and secured to both the backing and to the back of the frame by an adhesive. The excess metallized plastic film is trimmed and the assembly is subjected to heat for a short time to cause the stretched metallized plastic film to shrink somewhat. Suitable mounting brackets are affixed to the frame. The result is a very flat, light-weight mirror. The main drawback of the mirror is that it is very labor intensive, since the adhesive is manually applied and the metallized plastic film is hand-wrapped about the frame, similar to gift wrapping a package. The resultant mirror often exhibits deformations due to wrinkling of the metallized plastic film unless the hand-wrapping is carefully done.
The present invention improves upon such prior art metallized plastic film mirrors by eliminating a majority of the hand operations, machine forming the frame from aluminum roll stock and reducing the likelihood of wrinkling of the metallized plastic film by supporting it at a smooth peripheral edge that is raised from the frame surface